Background: Gastric cancer is an important cause of death among racial/ethnic minorities in the U.S. The objective of this study was to investigate racial disparities in survival among gastric cancer patients within demographic and disease subgroups. Methods: Patients diagnosed with invasive epithelial gastric cancer between 2006-2015 were identified from the California Cancer Registry. Cox proportional hazards regression was used to identify factors associated with survival among non-Hispanic whites (NHWs, n=7,475), non-Hispanic blacks (NHBs, n=1,246), Hispanics (n=6,274), and Asians/Pacific Islanders (APIs, n=4,204). Survival was compared across race/ethnicity within subgroups of demographic and disease factors. Five-year relative survival was also calculated within subgroups. Results: There were notable differences in patient characteristics by race/ethnicity, but predictors of survival were similar for each group. Overall, APIs (HR=0.83, 95% CI: 0.79, 0.88, p<0.0001) and Hispanics (HR=0.94, 95% CI: 0.90, 0.99, p=0.0104) had better survival than NHWs, but NHBs and NHWs did not have different prognosis (HR=1.06, 95% CI: 0.98, 1.15, p=0.2237). The survival advantage of APIs persisted in nearly every demographic and disease subgroup, but Hispanics and NHBs had similar survival as NHWs in most groups. Race was not a significant predictor of survival among those with public or no insurance and patients with cardia tumors. Conclusions: There are some differences in survival by race/ethnicity, but race/ethnicity alone cannot explain disparate outcomes in gastric cancer. Future studies, particularly ones that investigate the role of population-specific etiological factors and molecular tumor profiles, are needed to further understand factors associated with survival.
